In general, a paper coating latex is produced by emulsion polymerization. The polymerization conversion ratio of the paper coating latex does not reach 100%, which means that non-reacted monomers or volatile organic compounds remain in the latex, causing a foul odor during paper coating and drawing limitations in practical application.
To eliminate the petrochemical odor generated by non-reacted monomers and volatile organic compounds remaining in the paper coating latex, secondary polymerization is employed, in which a polymerization initiator is added to the latex which has already been through the reaction to polymerize non-reacted monomers. In another deodorization process, inactive gas or vapor is added under vacuum conditions to evaporate non-reacted monomers or volatile organic compounds.
The secondary polymerization has a problem in that volatile organic compounds still remain without being polymerized. The other deodorization process above also has the problems of enormous energy consumption, requiring additional facilities, and generation of bubbles and congelations. If these methods are running continuously, the odor will be reduced but polymerization productivity will be also reduced and the latex petrochemicals cannot be eliminated completely.